Bats confirmed host of SARS virus

Our scientists, in collaboration with research partners, identified bats as the natural reservoir of Severe Acute Respiratory Syndrome (SARS)-like coronaviruses.

The challenge

Elusive origin

Severe Acute Respiratory Syndrome (SARS) emerged in 2002-03 in southern China. At the time, the origin of the agent that caused the syndrome, the SARS coronavirus (SARS-CoV), remained elusive.

The SARS epidemic of 2003 is a perfect example of a previously unknown virus causing worldwide chaos as it spread from China to Hong Kong to as far as Canada.

The pandemic killed 774 of the 8094 people infected, a case fatality ratio of almost 10 per cent.

With cases diagnosed across the world, the pandemic had an impact on international travel, tourism and trade.

Our response

Likely host

In 2005 collaborative research involving four CSIRO scientists and other researchers from Australia, China and the United States found that bats are highly likely to be the natural host of the virus responsible for SARS.

While some of our most deadly zoonotic viruses originate in bats, bats are merely carriers of the virus and rarely develop the disease themselves.

The authors reported that some species of bats were the natural host of coronaviruses closely related to those responsible for the SARS outbreak. Such viruses, termed SARS-like coronaviruses (SL-CoVs), display greater genetic variation than SARS-CoV isolated from people or from civet cats.

The human and civet isolates of SARS-CoV nestle phylogenetically within the spectrum of SL-CoVs, indicating that the virus responsible for the SARS outbreak was a member of this coronavirus group.

The results

Bats confirmed as SARS origin

In 2013 a team of international scientists, led by Professor Shi Zhengli from Wuhan Institute of Virology, Chinese Academy of Sciences and CSIRO scientist Professor Linfa Wang, isolated a very close relative of SARS-CoV from horseshoe bats in China, confirming them as the origin of the virus responsible for the 2002-3 pandemic.

The results were published in the prestigious journal Nature. This finding will help governments design more effective prevention strategies for SARS and similar epidemics.

Dr Linfa Wang (centre) discussing SARS with colleagues in China.

Dr Linfa Wang (centre) discussing SARS with colleagues in China.

While researchers globally have previously used genetic sequencing to demonstrate that bats are the natural reservoirs of SARS-like CoVs, this is the first time live virus was successfully isolated from bats to definitively confirm them as the origin.

The team successfully isolated a SARS-like CoV, named SL-CoV WIV1, directly from faecal samples of Chinese Horseshoe bats using the world renowned bat virus isolation methodology developed by scientists at CSIRO’s Australian Animal Health Laboratory in Geelong.

Horseshoe bats are found around the world, including Australia and play an important ecological role. Their role in SARS-CoV transmission highlights the importance of protecting the bat’s natural environment so they are not forced into highly populated urban areas in search of food.

This work is part of CSIRO's ongoing commitment to protect Australia from biosecurity threats posed by new and emerging infectious diseases.